diff options
| -rw-r--r-- | drivers/vhost/tcm_vhost.c | 54 |
1 files changed, 30 insertions, 24 deletions
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c index 62058d7a562f..704e4f674776 100644 --- a/drivers/vhost/tcm_vhost.c +++ b/drivers/vhost/tcm_vhost.c @@ -430,40 +430,47 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd( * Returns the number of scatterlist entries used or -errno on error. */ static int vhost_scsi_map_to_sgl(struct scatterlist *sgl, - unsigned int sgl_count, void __user *ptr, size_t len, int write) + unsigned int sgl_count, struct iovec *iov, int write) { + unsigned int npages = 0, pages_nr, offset, nbytes; struct scatterlist *sg = sgl; - unsigned int npages = 0; - int ret; + void __user *ptr = iov->iov_base; + size_t len = iov->iov_len; + struct page **pages; + int ret, i; - while (len > 0) { - struct page *page; - unsigned int offset = (uintptr_t)ptr & ~PAGE_MASK; - unsigned int nbytes = min_t(unsigned int, - PAGE_SIZE - offset, len); + pages_nr = iov_num_pages(iov); + if (pages_nr > sgl_count) + return -ENOBUFS; - if (npages == sgl_count) { - ret = -ENOBUFS; - goto err; - } + pages = kmalloc(pages_nr * sizeof(struct page *), GFP_KERNEL); + if (!pages) + return -ENOMEM; - ret = get_user_pages_fast((unsigned long)ptr, 1, write, &page); - BUG_ON(ret == 0); /* we should either get our page or fail */ - if (ret < 0) - goto err; + ret = get_user_pages_fast((unsigned long)ptr, pages_nr, write, pages); + /* No pages were pinned */ + if (ret < 0) + goto out; + /* Less pages pinned than wanted */ + if (ret != pages_nr) { + for (i = 0; i < ret; i++) + put_page(pages[i]); + ret = -EFAULT; + goto out; + } - sg_set_page(sg, page, nbytes, offset); + while (len > 0) { + offset = (uintptr_t)ptr & ~PAGE_MASK; + nbytes = min_t(unsigned int, PAGE_SIZE - offset, len); + sg_set_page(sg, pages[npages], nbytes, offset); ptr += nbytes; len -= nbytes; sg++; npages++; } - return npages; -err: - /* Put pages that we hold */ - for (sg = sgl; sg != &sgl[npages]; sg++) - put_page(sg_page(sg)); +out: + kfree(pages); return ret; } @@ -496,8 +503,7 @@ static int vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *tv_cmd, pr_debug("Mapping %u iovecs for %u pages\n", niov, sgl_count); for (i = 0; i < niov; i++) { - ret = vhost_scsi_map_to_sgl(sg, sgl_count, iov[i].iov_base, - iov[i].iov_len, write); + ret = vhost_scsi_map_to_sgl(sg, sgl_count, &iov[i], write); if (ret < 0) { for (i = 0; i < tv_cmd->tvc_sgl_count; i++) put_page(sg_page(&tv_cmd->tvc_sgl[i])); |